Evidence that the violation was the agency's policy or custom.

The Monell requirement

In Monell v. Department of Social Services (1978), the Supreme Court held that local governments can be sued under Section 1983, but only when the violation results from an official policy or a widespread custom. A municipality is not liable merely because it employs someone who violated the Constitution. In City of Canton v. Harris (1989), the Court added that a failure to train can be the basis for liability when it amounts to deliberate indifference to the rights of the people officers encounter.

Why these claims matter

Individual officers may be protected by qualified immunity. Municipalities are not. A well-supported municipal claim can therefore survive when the claim against the individual officer does not, and it is the kind of claim that leads an agency to change its practices.

Finding the pattern

Pattern evidence is built from many sources: earlier lawsuits and settlements, complaint records, use-of-force statistics, news reports, findings by oversight bodies and the Department of Justice, and interviews with people who experienced the same conduct. The work is to identify incidents that are truly similar and to document each of them well enough to be used in court.

Policy on paper and policy in practice

An agency's written policy may be sound while its actual practice is not. Comparing the policy manual with what officers were trained to do, what supervisors tolerated, and what happened after earlier complaints shows whether the written policy was the real one.